[1] Observational records and reconstructions from tree rings reflect premonsoon (March to May) temperature cooling in the western Himalaya during the latter part of the 20th century. A rapid decrease of minimum temperatures at around three times higher rate, as compared to the rate of increase in maximum temperatures found in local climate records is responsible for the cooling trend in mean premonsoon temperature. The increase of the diurnal temperature range is attributed to large scale deforestation and land degradation in the area and shows the higher influence of local forcing factors on climate in contrast to the general trend found in higher latitudes of the northern Hemisphere.

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Five teak trees in northem Thailand were selected for the study of vessels in terms of dendroclimatology. The tree rings were divided into earlywood and latewood, and fourparameters (average vessel area, average vessel diameter, average conductive area, and vessel density) were measured by automatie image analysis technique to obtain 50-year (1947-1996) time series. Two questions were addressed: 1) How strongly are the vessel characteristics related to climate and 2) are these relationships different from those of ring widths? All vessel parameters of the total ring and of the earlywood were negatively correlated with precipitation during the transitional period between the dry and the wet season. The latewood vessel parameters, however, are negatively correlated with J une temperature. The climatic signals of the vessel parameters and of the tree-ring width are different from each other.

Ring-width chronologies of Himalayan cedar (Cedrus deodara (D. Don.) G. Don.), Himalayan pine (Pinus wallichiana A. B. Jackson), and Himalayan spruce (Picea smithiana (Wall.) Boiss.) from the western Himalayan region, India, have been used to reconstruct mean April–May temperature back to A. D. 1698. The reconstruction correlates significantly with the average April–May instrumental temperature record (r= +0.62, 1876–1988) and is characterized by annual to multiyear fluctuations. The most striking feature of the present reconstruction is the absence of any warming trend in the 20th century. Relationships between the mean April–May temperature for the western Himalayan region, Indian summer monsoon rainfall, and Southern Oscillation Index indicate that the tree-ring chronologies, as surrogate temperature records, will provide valuable data for climate change studies with regional and global perspectives.

The Himalayan region plays a very important role in influencing the regional and extra-regional circulation system. Long-term instrumental or proxy climate records for this region are scant, but are essential for a global perspective of climate variability. A 598-year (AD 1390-1987) reconstruction of spring (March-May) temperature has been derived for the first time for the western Himalayan region, India using a well replicated ring-width chronology of Himalayan cedar (Cedrus deodara (D. Don) G. Don). The reconstruction showing annual to multi-year episodes of cool and warm springs is well correlated with the instrumental record of spring temperature for 1876-1987 (r = 0.53, p < 0.001). Prominent large-magnitude century-scale excursions in negative anomalies of spring temperature which might reflect the regional influence of the ‘Little Ice Age’ are not indicated in our data. The seventeenth century experienced monotonically warm springs. Neither recostruction or instrumental data provide evidence of warming during the last few decades of this century which could be attributed to anthropogenic causes. A strong out-of-phase relationship between the instrumental sprin-temperature record over the western Himalayan region and sea-surface temperatures (SSTs) of ensuing months (June-May) over the equatorial Pacific Ocean has been noted. This suggests that temperature responsive tree-ring chronologies from the Himalayan region could also serve as a valuable proxy of the Southern Oscillation.